• Korean Management Science Review
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• v.25 no.1
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• pp.107-121
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• 2008

As to more efficiently manage the inventory in the retail supply chain and to meet the customer demand in a timely manner, vendor-managed inventory (VMI) has been widely accepted, which manages inventory in the retail supply chain via sharing information and collaborating with the retailers. Applying VMI generates vendor-managed inventory/distribution problem (VMIDP), which involves inventory management for both the vendor and the retailers, and the design of vehicle routes for delivery, to minimize the total operating cost in the supply chain. In this paper, we suggest a mixed integer programming (MIP) model to obtain the optimal solution for VMIDP in a two-echelon retail supply chain, and develop an efficient heuristic based on the operating principles of the MIP model. To evaluate the performance of the heuristic, its solution was compared with the one of the MIP model on a total of twenty seven test problems. As a result, the heuristic found optimal solutions on seven problems in a significantly reduced time, and generated a 4.3% error rate of total cost in average for all problems. The heuristic is applied to the case problem of the local famous franchise company together with GIS, showing that it is capable of providing a solution efficiently in a relatively short time even in the real world situation.

• IE interfaces
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• v.16 no.3
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• pp.280-290
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• 2003

Many firms are trying to optimize their production and distribution functions separately, but possible savings by this approach may be limited. Nowadays, it is more important to analyze these two functions simultaneously by trading off the costs associated with the whole. In this paper, I treat a production and distribution planning problem for single-period inventory products comprised of a single production facility and multiple customers, with the aim of optimally coordinating important and interrelated decisions of production sequencing and vehicle routing. Then, I propose a hybrid genetic algorithm incorporating several local optimization techniques, HGAP, for integrated production-distribution planning. Computational results on test problems show that HGAP is effective and generates substantial cost savings over Hurter and Buer's decoupled planning approach in which vehicle routing is first developed and a production sequence is consequently derived. Especially, HGAP performs better on the problems where customers are dispersed with multi-item demand than on the problems where customers are divided into several zones based on single-item demand.

• Journal of the Korea Safety Management & Science
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• v.3 no.3
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• pp.77-86
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• 2001

An operational strategy for inventory control on finished goods in the distribution system has been given attention to many enterprises and many studies regarding this field have been done and is also on-going currently. Many of these studies represented a large scale distribution network with a unified formulation by using defined symbols. These methods have provided the systematic approach of the distribution network but they are impossible to applying the reality system due to not considering the service rate of demand and treating the shortage of inventory. In order to overcome these unrealistic problems, the novel safety stock policy of responding to customers' inventory distribution network is suggested. this paper explores the transportation between Central Distribution Center(CDC) and Regional Distribution Center(RDC). Especially, the relation of transportation cost between CDC and RDC and cost of inventory control according to safety inventory with service level are emphasized. We could obtain the good results of this study by determining the optimal safety stock considering the various variables and constraints.

• Journal of Distribution Research
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• v.7 no.1
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• pp.1-20
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• 2002

Many of logistics-related research in automobile industry has focused on inbound logistics and procurement. Research into outbound logistics is relatively few. As a starting research into outbound logistics in automobile industry, this paper examined its logistics network problems with three aspects - location strategy, inventory strategy and transportation strategy. We proposed alternatives of logistics network design resolution, and presented three practical scenarios based on those alternatives. Based on interview, on-site visit and internal data collection processes, we identified major domestic outbound logistics problems such as redundant logistics bases, inefficient delivery policy, insufficient inventory capacity, inventory stock quality deterioration, inefficient transportation system, and etc. In order to cope with those problems, we proposed such strategic alternatives as introduction of hub-and-spoke system, integration of logistics bases, introduction of (automatic) parking building, diversification of transportation mode, and etc. At the same time, we constructed three practically executable scenarios based on those ideas. The first is "Center Hub" scenario, the second is "Metropolitan Hub" scenario. The third and last scenario is "Regional Consolidation of Warehouses (distribution centers)".

• The Korean Journal of Elementary Counseling
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• v.7 no.1
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• pp.37-66
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• 2008

This study has been carried out with the aims of developing a comprehensive inventory of peer relation problems, which is based on the Korean Inventory of Interpersonal Problems Circumplex scales (KIIP-C). It also aims to examine reliability and validity of the inventory, and provide a preliminary norms. For the current study, inventory items were culled from the following sources: the Korean Inventory of Interpersonal Problems Circumplex scales (KIIP-C), various current scales dealing with peer relations of children, and a survey of children's peer relation problems. The preliminary items for each scale were administered to 220 fourth through sixth graders. The resulting skewness of distribution, kurtosis, mean and standard deviation, item-total correlation, internal consistency, and meanings of the items were comprehensively considered in selecting the final 64 items. In order to check on reliability, internal consistency, convergence and discrimination reliability of the final items and scales, the data were collected from 1,046 fourth through sixth graders currently attending four elementary schools. The study results can be summarized as follows. Internal consistency of the inventory of peer relation problems showed the range between .70-.94 (median value of .75), split-half reliability between .67-.83 (median value of .75), and test-retest reliability between .69-.88 (median value of .81). Inter-correlation of 8 scale scores and factor analysis results of individual ipsative scores showed that the circumplex property of inventory of peer relation problems is appropriate. Regarding correlations between various existing indices and scales related to peer relation problems, both convergence reliability and discrimination reliability were found to be fair. When the scale scores for the inventory of peer relation problems compared according to the factors of gender and grade, the primary effects of gender and grade were statistically meaningful whereas effects of interaction between gender and grade were not. This study can be considered meaningful in that it constructed an inventory for a comprehensive evaluation of peer relation problems specific for children and provided preliminary norms.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.13 no.21
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• pp.61-72
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• 1990

In the past, a fundamental technique in inventory control system was to rank the items of a inventory from a distribution by value to draw an ABC curve. Unfortunately the use of ABC categorization technique has created problems and introduced some gross errors into the inventory control system. First, the author considers the possible applications of the technique in the real world and then attempts to discuss ABC fallacies through the literatures. Finally, an inventory categorization algorithm by the principal component analysis is derived and a numerical example is also presented to illustrate the algorithm.

• Management Science and Financial Engineering
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• v.17 no.2
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• pp.1-21
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• 2011

This paper considers an integrated inventory-distribution system with a fleet of heterogeneous vehicles employed where a single warehouse distributes a single type of products to many spatially distributed retailers to satisfy their dynamic demands. The problem is to determine order planning at the warehouse, and also vehicle schedules and delivery quantities for the retailers with the objective of minimizing the sum of ordering cost at the warehouse, inventory holding cost at both the warehouse and retailers, and transportation cost. For the problem, we give a Mixed Integer Programming formulation and develop a Lagrangean heuristic procedure for computing lower and upper bounds on the optimal solution value. The Lagrangean dual problem of finding the best Lagrangrean lower bound is solved by subgradient optimization. Computational experiments on randomly generated test problems showed that the suggested algorithm gives relatively good solutions in a reasonable amount of computation time.

• Korean Management Science Review
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• v.11 no.1
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• pp.73-90
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• 1994

Recently the recongnition of Logistics becomes important to enterpries as a means for improving their competition, but the Korea enterpries falls for far behind in management techniques for analyzing realities and problems in the Logistics compare to the advanced countries. Especially the function of inventory control which is most undeveloped in them should be improved in Korea. Inventory is very important in Logistics, but there exists trade-off between inventory level and customer in the service level. It is difficult to coordinate both the reduction in the inventory level and the enhancement in the service level. Its effective technique is a DRP system. In general, it deals with arborescent distribution network in which a given channel member has a single source of supply. This article aims to present a DRP system, and more a DRP system which is flexible and responsive in the multisourcing, multi-echelon distribution network. Related research issues are discussed. Finally, using a DRP system on logistics and the management performance. So we can help the physical distribution improvement of the Korean enterprises.

• Journal of the Korea Society of Computer and Information
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• v.6 no.4
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• pp.163-167
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• 2001

Many of these studies represent a large scale distribution network with a unified formulation by using defined symbols. This can be evaluated as a valuable progress toward accomplishing of a systematic approach the area of distribution network. Unfortunately. transportation problem and inventory policy applied in these studies have an assumption of using an unique supplier for calculating the transportation cost among each distribution echelon. This assumption can cause many problems such that transportation problem is assumed as linear problem, too many number of distribution center are allowed to operate and many more. In order to overcome above unrealistic problems, we developed an algorithm of responding to customers' demand under the refill allowance of same level supply as anew constructional method of inventory distribution network. When backorders are happened in regional distribution center, this algorithm allows transferring finished goods to customer directly from vicinal Regional distribution center instead of existing central distribution center for quick response.

• Journal of the Korea Society for Simulation
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• v.10 no.1
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• pp.35-50
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• 2001

Managing multi-echelon inventory systems has gained importance over the last decade mainly because integrated control of supply chains consisting of several processing and distribution stages has become feasible through modern information technology. Determination of optimal inventory policy for multi-echelon supply chain is made difficult by the complex interaction between the different levels. In this paper, we investigate performance of five inventory policies (fixed quantity order policy, fixed interval order policy, compromised order policy, lead time-fixed quantity order policy, and mixed order policy) in a multi-echelon supply chain by using a simulation model constructed with AweSim simulation language. The results of the simulation study show that the mixed order policy is the best among five inventory policies in the most test problems except the case when the stockout cost per unit is much higher than the inventory holding and transportation costs per unit.